The present invention relates to a tunneling method and apparatus. More particularly, this invention concerns a method of and arrangement for lining a tunnel with a succession of arches each having an arcuate upper part for engaging the tunnel roof and lower parts juxtaposable with the tunnel sides and engageable with the tunnel floor for supporting the respective upper part.
It is frequently desired to line a tunnel, by which here is meant a horizontal or nearly horizontal underground passage also often referred to as an added, level or drift, with a succession of lining arches. Each of these arches is normally formed of steel or iron and is bolted to the adjacent arches so as to form a rigid lining within the tunnel. Such a lining prevents the tunnel from caving in and is typically used in tunnels which will be used for substantial traffic over a long period of time.
In order to make the tunnel lining operation go as quickly as possible it is standard practice to at least partially preassemble the lining arches. Thus the various parts that constitute the upper part of the lining are normally preassembled in the mine at a location distant from the face thereof, the face here referring generally to the tunnel area adjacent the end at which it is being driven.
In the most common arrangement a fork-like assembly head is displaceable relative to an installation wagon that can be displaced between the assembly location in the tunnel and the face where the lining arches are installed immediately behind the tunneling equipment. This installation wagon is displaceable along two rails which are hung from the lined part of the mine. The assembly and installation head is thus displaced ack to the assembly location and lowered so that the upper arch portion can be preassembled on it. After this preassembling the head is again lifted and the preassembled roof part is moved along the mine up to the face. Then it is positioned against the mine roof and the side portions or lower portions of the respective arch are secured to the upper portion so as to complete this arch.
Although such a procedure is in principle more efficient that an operation wherein the entire arch is assembled piece-by-piece at the face, the arrangement has the considerable disadvantage that it ties up the installation car doing preassembly of the upper arch part. Nonetheless since each upper arch part normally comprises several different parts, usually a few arcuate channels along with some sheet-metal sheathing it is not possible to preassemble the upper arch part simply on the mine floor. The installation head fits closely with the upper arch part so that assembly of this part on it is a relatively simple matter.
Other disadvantages of this known system is that the installation car often takes up considerable room in the tunnel so that it cannot be moved back and forth for installing lining arches while tunneling is going on. Thus when a lining arch is to be installed all of the other operations in the tunnel must be brought to a halt, idling expensive equipment and wasting valuable man-hours. This is particularly the case when the tunnel is being driven by drilling and blasting. Furthermore, the use of a hanging installation car is highly disadvantageous in that the car often tends to swing somewhat from side to side so that it is necessary to advance the assembled upper arch portion very slowly from the assembly location to the mine face in order to prevent it from striking the sides of the tunnel or equipment therein and damaging either itself or whatever it strikes. Not only does the hanging installation car have to move very slowly, therefore slowing down operations further, but it is very difficult accurately to position the upper arch portion from such a hanging car. For this reason it is a relatively lengthy operation to accurately position the upper arch portion before the lower portions can be secured thereto. It is also noted in this respect that the upper arch portion cannot simply be pressed against the mine roof before the lower arch portions are in place so as to prevent cave-ins in back of the tunneling machinery.